Visual Basic

Imports System.IO
Public Class ExtractIcon
    Private Declare Function ExtractIconEx Lib "shell32.dll" Alias "ExtractIconExA" _
            (ByVal lpszFile As String, _
             ByVal nIconIndex As Integer, _
             ByRef phiconLarge As Integer, _
             ByRef phiconSmall As Integer, _
             ByVal nIcons As Integer) As Integer
    Private Declare Function DestroyIcon Lib "user32.dll" (ByVal hIcon As Integer) As Integer
    Private Declare Function ExtractIcon Lib "shell32.dll" Alias "ExtractIconA" (ByVal hInst As Integer, ByVal lpszExeFileName As String, ByVal nIconIndex As Integer) As Integer

    'calls API to determine how many icons are embedded in the file
    Private Shared Function GetNumberOfIcons(ByVal fl As String) As Integer
        Return ExtractIconEx(fl, -1, 0, 0, 0)
    End Function

    'Extracts each icon from the file given, and saves it to the destination directory
    Public Shared Sub ExtractIconsFromFile(ByVal file As String, ByVal list As ListView)
        Dim info As New IO.FileInfo(file)
        Dim numicons As Integer  ' number of regular icons in the file
        Dim retval As Integer  ' return value
        Dim hInstance As IntPtr = System.Runtime.InteropServices.Marshal.GetHINSTANCE(System.Reflection.Assembly.GetExecutingAssembly.GetModules()(0))


        'Make sure we have an image list for our listview
        If list.LargeImageList Is Nothing Then
            Dim iconImageList As New ImageList
            iconImageList.ImageSize = New Size(32, 32)
            iconImageList.ColorDepth = ColorDepth.Depth32Bit
            list.LargeImageList = iconImageList
        End If

        list.Items.Clear()
        numicons = GetNumberOfIcons(info.FullName)
        For i As Integer = 0 To numicons - 1
            retval = ExtractIcon(hInstance, info.FullName, i)
            If retval > 0 Then
                Dim ico As Icon = Icon.FromHandle(New IntPtr(retval))
                list.LargeImageList.Images.Add(retval.ToString, ico)
                list.Items.Add(retval.ToString, retval.ToString)
            End If
            DestroyIcon(retval)
        Next
    End Sub
End Class

Select Case cmbLetters.Text
 Case "A"
   lTemp = 10
 Case "b"
   lTemp = 8
 Case Else
   lTemp = 0
 End Select

amaneet wrote:

I wanted to know in which condition I should write the following line of code.I mean what is the utility of that.